President Donald Trump's call to declassify documents used to obtain a Foreign Intelligence Surveillance Act (FISA) warrant and other items included in the FBI's Russia investigation could reveal confidential sources and how the intelligence community works, Judge Andrew Napolitano said he fears Tuesday.

"I’ve been a critic of the intelligence community," Napolitano, the senior junior analyst for Fox News, said on "Fox & Friends" program. "I also respect that a lot of them risk their lives to get this information for us. It might be a little bit too much transparency."

He said he understands the argument about releasing information, including about how a dossier on Trump was used to obtain a surveillance warrant against his campaign aide, Carter Page.

"I have been a harsh critic of FISA," said Napolitano. "It purports to change the constitutional standard. But, if you are going to expose what went to FISA in this case, then FISA will no longer be secret and helpful."

Meanwhile, there are many documents that still can't be made public, such as items showing what was presented to a grand jury to evidence a thought process, or documents that are the result of confidential or undercover sources, said Napolitano.

"Don't expect these documents to come out today because just like the last time the president ordered this stuff declassified, dozens of pairs of eyes have to look at each document," he said. "Some things, even the president can't order public. He can order declassified what he wants."

Judge Andrew Napolitano fears President Donald Trump's call to declassify documents used to obtain a FISA warrant and other items included in the FBI's Russia investigation could reveal confidential sources.